SimpleTemplate::SimpleTemplate(boost::string_ref text)
{
static char const rawMarker[] = "@@";
static boost::string_ref const marker(rawMarker, sizeof(rawMarker) - 1);
auto beg = text.find(marker);
while (beg != boost::string_ref::npos) {
m_literals.emplace_back(text.data(), beg);
text.remove_prefix(beg + marker.size());
auto end = text.find(marker);
if (end == boost::string_ref::npos) {
std::string& lit = m_literals.back();
lit.reserve(lit.size() + marker.size() + text.size());
lit.append(marker.data(), marker.size());
lit.append(text.data(), text.size());
assert(m_literals.size() == m_insertionKeys.size() + 1);
return;
}
m_insertionKeys.emplace_back(text.data(), end);
text.remove_prefix(end + marker.size());
beg = text.find(marker);
}
m_literals.emplace_back(text.data(), text.size());
assert(m_literals.size() == m_insertionKeys.size() + 1);
}
double CInfixExpressionCalculator::ParseDouble(boost::string_ref &ref)
{
SkipSpaces(ref);
double value = 0;
bool parsedAny = false;
while (!ref.empty() && std::isdigit(ref[0]))
{
parsedAny = true;
const int digit = ref[0] - '0';
value = value * 10.0 + double(digit);
ref.remove_prefix(1);
}
if (!parsedAny)
{
return std::numeric_limits<double>::quiet_NaN();
}
if (ref.empty() || (ref[0] != '.'))
{
return value;
}
ref.remove_prefix(1);
double factor = 1.0;
while (!ref.empty() && std::isdigit(ref[0]))
{
const int digit = ref[0] - '0';
factor *= 0.1;
value += factor * double(digit);
ref.remove_prefix(1);
}
return value;
}
double CInfixExpressionCalculator::ParseExprSum(boost::string_ref &ref)
{
double value = ParseExprMul(ref);
while (true)
{
SkipSpaces(ref);
if (!ref.empty() && ref[0] == '+')
{
ref.remove_prefix(1);
value += ParseExprMul(ref);
}
else if (!ref.empty() && ref[0] == '-')
{
ref.remove_prefix(1);
value -= ParseExprMul(ref);
}
else
{
break;
}
}
return value;
}
void CInfixExpressionCalculator::SkipSpaces(boost::string_ref &ref)
{
size_t i = 0;
while (i < ref.size() && std::isspace(ref[i]))
++i;
ref.remove_prefix(i);
}
inline boost::string_ref remove_leading_spaces(boost::string_ref string, const char* spaces = " \t\r\n")
{
auto pos = string.find_first_not_of(spaces);
if (pos == std::string::npos) pos = string.size();
string.remove_prefix(pos);
return string;
}